Dividers and calipers



E. H. HERRSTRUM DIVIDERS AND CALIPERS Filed Feb. 6, 1922 Patented Oct.21, 1924.

UNITED STATES PTENT OFFICE.

ERNEST H. HERRSTRULII, 03E' IHIIJIN, ILLINOIS.

LDIVIDERS AND CALIIE'ERS.

Application filed February G, 1922.

[o all whom t may conce/m.'

Be it known that I, ERNEST H. I-Innns'riiuir, a citizen of the UnitedStates, residing at llIoline, in the county of Rock Island and Stat-e ofIllinois, have invented certain new and useful Improvements in Dividersand Calipers, of which the following is a specilication.

This invention relates to dividers, cali'- pers and similar instruments,and has for its principal object to permit them to be folded into acompact form that will occupy a minimum of space.

Heretofore locking devices for securing the legs of these instruments inadjusted position have `been more or less rigidly fixed to one leg so asto extend beyond the other leg, whether the instrument was in folded orextended condition. It is therefore another object of my invention toprovide locking means that can be foldedwi'th the legs and will liesubstantially within the width of the legs. Y

Another object of the invention is to provide an impro-ved micrometeradjustment for giving the legs the exact position desired after theyhave been locked in approximately that position.

Further objects of the invention will b ecome apparent as thedescription is read in connection with the accompanying drawing showinga selected embodiment of the invention in which v n Fig. 1 illustratesan elevation o f a pair of dividers embodying the invention; and

Fig. 2 is a transverse section on the line 2-2 of Fig. 1.

I have shown the invention as appliedto dividers, but the. applicationto similar instruments will be clear to those skilled in the art.

In the drawings, 10 and 11 indicate legs of a pair of dividers hinged at12 and provided with suitable points 13 and 14. The leg 10 is providedwith a guide 15 substantially rectangular in form, in which a block 1Gis adapted to reciprocate under the control of a thumb-screw 17 passingthrough the block and swiveled to the leg 10. As here shown, the screwhas a shoulderV 18 adjacent to the head and is upset at 19 on the insideof the leg 10, and a spring 2O serves to take up any slack in theconstruction. The block 16 is provided with a pintle 21 upon which ispivoted a linkv 22 having a short arm 23 and a long slotted arm SerialNo. 534,395.

24. rIhe short arm is preferably of a length to reach from the rightedge of the leg 11 to the extreme position of the pintle 21 to the leftin 1Eig. 1. VIhe slotted arm is suiiiciently long to permit fullextension of the legs of the dividers and is slidably connected with theleg 11 by a thumb-screw 25` which preferably through the leg 11 and hasa shoulder 26 to lie against the arm 24 on opposite sides of the slot27.

In use, when it is desired to extend the dividers, the thumb-screw 25 isloosened and the legs spread apart to the approximate distance and thescrew 25 tightened. rI`hen the screw 17' is turned in the appropriatedirection to give the points 13 and li the exact nicety of adjustmentrequired. The movement of the block 16 under the action of the screw 17permits the legs to be given a relative movement by a very slow motionthat enables the operator to very accurately set the dividers or otherinstrument to which the invention is applied, and the spring 2O takes upany lost motion that may be in the parts and secures the parts in theposition of adjustment. When the instrument is to be put away, the screw25 is loosened and the legs and link moved from the position indicatedin dotted lines in F ig. 1 to approximately the position shown in solidlines in F ig. 1 when the long arm of the link will lie on the leg 11and the short arm will lie across the legs substantially as illustrated.The invention, therefore, makes it possible to fold the instrument verycompactly so that it will occupy much less space than the constructionnow in common use, and the micrometer adjustment will enable theaccurate setting of the points 13 andl 14, and serve to hold themsecurely in the adjusted position. rIhe guide 15 reinforces the leg 10and makes it possible to extend the slot for the block 16 well into theleg and thereby provide ample movement for the block within a verynarrow instrument.

I am aware that changes may be made in the form, construction andarrangement of the invention, as set forth in the selected einbodimentherein, without departing from the scope or sacrificing any of itsmaterial advantages, and I therefore reserve the right to make all suchchanges as fairly fail within the scope of the following claims.

I claim:

1. The combination of a pair of legs hinged together, a link having along arm provided with a longitudinal slot and a short arm at an angleto the long arm, nieans for pivotally and adjustably connecting theshort arm to one leg, and adjustable ineens carried by the other leg andeo-operating With the slotted arni to Secure it thereto, Said long armbeing adapted to lie Within the Width of the two legs when the lege arebrought into closed positions.

2.v The combination of e peil' of lege hinged together, n link having enerin substantially equal to the Width ot the two legs and e long`slotted erin fili an angle thereto, Ineens for pivoting the short erinto one leg, and mee-ns for slidably connecting the Slotted erm to theother leg, S21-id slotted a-rin being adapted to lie Within the Width'of the two legs when the legs are brought into closed positions.

3. The combination of a pair of legs hinged together, u guide on one ofSuid legs, e block slidable in seid guide, a screw swiv eled to said legandengaging said block, :i link pivoted to said block :1nd having :innngulzn' slotted erin, and menne for Securing said slotted a-rni to theother leg.

4. The combination of e pair ol legs hinged together, a guide extendingtrainsversely to one of said legs, n, block slidably mounted in saidguide, u spring insinting the inovenient of said guide in one direction,u serew Swivelecl to Said leg und engaging Said block, :i link pivoteilto Said blork :unl having an angular slotted erin, unil menne` forSecuring' Said slotted nrni to the other leg.

ERNEST H. HERRSTR UM.

